The extant literature suggests that relational aggression appears in early childhood, and gradually increases throughout adolescence. However, very little research has examined the growth of relational aggression from adolescence to emerging adulthood. In addition, research generally examines socializing factors of relational aggression, such as parenting, peers, siblings, or media in isolation. Accordingly, the aim of the current study was to examine these socializing factors conjunctively as predictors of the growth of relational aggression over time. Participants consisted of 500 adolescents who completed several questionnaires over a 7-year period (between ages 14-20 on average). Results revealed that the vast majority of individuals (88%) showed low levels of relational aggression that decreased over time. Conversely, a small proportion of individuals (12%) had high, increasing levels of relational aggression between adolescence and emerging adulthood. High levels of maternal psychological control, sibling hostility, and relational aggression in the media at the initial time point all predicted being in the high and increasing group.